Precure process



United States Patent 3,510,249 PRECURE PROCESS Myrtle J. Spangler, Danville, Va., assignor to Dan River Mills, Incorporated, Danville, Va., a corporation of Virginia No Drawing. Filed Apr. 6, 1966, Ser. No. 540,497 Int. Cl. D06m 13/12 US. Cl. 8-1163 8 Claims ABSTRACT OF THE DISCLOSURE Process of producing crease-resistant textiles such as sensitized textiles for use in the manufacture of durable press articles including the steps of impregnating a cellulosic textile with a crease-proofing nitrogen-containing compound, heating the impregnated textile to dry and set it in the absence of a curing catalyst for said crease-proofing compound, impregnating the resulting dried and set textile with a curing catalyst for said crease-proofing compound and drying the resulting catalyst impregnated textile to a condition suitable for shipment, storage and/or handling in the manufacture of articles therefrom whereby the resulting catalyst-impregnated textile is characterized by a greatly reduced formaldehyde odor.

This invention is directed to novel processes for imparting crease-resistance to cellulosic textiles and to novel processes for producing sensitized textiles for use in the manufacture of durable press articles.

It is well known that textiles can be provided with crease-resistance by treatments with a large variety of water-soluble or water-dispersible, nitrogen-containing compounds, such as, urea-formaldehyde condensates, triazone formaldehyde condensates, e.g., 1,3 dimethylol- 3,4,5,6 tetrahydro (2 hydroxyethyl) s triazin 2- one and 1,3 dimethylol 3,4,5,6 tetrahydro 5 ethyls-triazin-Z-one, hereinafter referred to as hydroxyethyl triazone and ethyl triazone respectively, melamine-formaldehyde condensates, formaldehyde condensates of ethylene urea, formaldehyde condensates of 4,5-dihydroxy- 2 imidazolidinone, e.g., 1,3 dimethylol 4,5 dihydroxy-2-imidazolidinone, and alkylated derivatives of such compounds from lower alkanols, e.g., 1,3-dimethoxymethyl 4,5 dihydroxy 2 imidazolidinone, and mixtures thereof. Heretofore, these nitrogen-containing creaseproofing compounds were applied to fabrics in the form of an aqueous solution which also contained acidic or basic catalysts and, if desirable, other additives for providing special effects, including softeners, lubricants, hand-modifiers, water-repellents, strain-repellents and the like. It was obviously necessary for such catalysts and additives to be compatible with the crease-proofing compound and, thus, in some cases, worthy catalysts and/0r additives were ruled out simply because they are incompatible with the crease-proofing compound being used.

It is the present practice of some fabric manufacturers to make fabric for use in durable press garments by impregnating a cellulosic fabric, such as polyester-cotton blends, with an aqueous solution of a textile crease-proofing compound, plus catalyst, such as 1,3-dimethylol-4,5- dihydroxy-Z-imidazolidinone, and partially drying the impregnated fabric at a temperature below the polymerization, insolubilization or curing temperature of the creaseproofing compound to retain a specified amount of moisture in the impregnated, partially dried fabric, thereby sensitizing the fabric. The resulting sensitized fabric is then sold and shipped to the garment manufacturer who cuts and sews it and otherwise forms the desired garment therefrom; imparts a crease or other shape to the garment,

such as by pressing; and thereafter cures the sensitized fabric of the garment to insolubilize the crease-proofing compound contained by it. Various methods for imparting durable creases and press-free areas to garments have been disclosed in the prior art and reference is made to United States Patents 2,974,432; 3,096,524; 3,138,802; 2,950,553; 2,846,337 and 3,025,622.

The manufacture and use of sensitized fabrics in making durable press garments, at the present time, is almost completely limited to the use of l,3-dimethylol-4,5-dihydroxy 2 imidazolidinone as the crease proofing compound. One reason for this is the high formaldehyde odor present in the dried sensitized fabric when other creaseproofing compounds are used as compared with the relatively low odor when using the above-named compound. The odor problem is particularly significant when large amounts of sensitized fabric are laid out on the cutting tables in garment factories and sometimes results in noxions and hazardous Working conditions. This problem is not entirely eliminated when using the 1,3-dimethylol- 4,5-dihydroxy-Z-imidazolidinone.

It is a principal object of this invention to provide novel processes for producing crease-resistant fabrics or sensitized fabrics for use in the manufacture of durable press garments.

Another object is the provision of such novel processes wherein there can be used curing catalysts and/ or additives which are incompatible in the same aqueous solution with the crease-proofing compound employed.

Another object is the provision of such novel processes wherein the formaldehyde odor is greatly reduced or eliminated in the treated fabric.

A further object is the provision of such novel processes wherein the finally cured fabric is of improved crease-resistance and tensile strength as compared to finally cured fabrics treated by heretofore known processes.

Additional objects and advantages are apparent in the following detailed description.

This invention is based on the discovery that the abovelisted advantages can be obtained by impregnating a cellulosic textile with a nitrogen-containing crease-proofing compound and heating to cure said compound in said textile in the absence of curing catalysts therefor and thereafter applying a curing catalyst to the thus treated textile. Subsequently, the textile can be dried, shipped to garment makers, cut and sewn into garments and pressed and cured to produce durable press garments. Alternatively, the treated textile after application of the curing catalyst can be cured in the flat to produce creaseresistant fabrics.

Any of the nitrogen-containing compounds set forth hereinbefore can be employed in the present invention. However, it is preferred to employ 1,3-dimethylol-4,5-dihydroxy-Z-imidazolidinone or l,3-dialkoxymethyl-4,5-dihydroxy-Z-imidazolidinone which are characterized by greater stability when applied to cellulosic textiles.

The crease-proofing compounds are conveniently aplied to cellulosic fabrics as an aqueous solution having a solids content which can be varied over a wide range, preferably 2% to The aqueous treating solution can also contain other ingredients for providing special or desired effects, such as softeners, wetting agents, whiteners, lubricants, water-repellents, soil-repellents, and the like, which are compatible in aqueous solution with the crease-proofing compound. If incompatible, such ingredients can be applied with the catalyst at a later stage in the process as hereinafter described.

The application of the crease-proofing compound to the fabric to be crease-proofed can be carried out in any convenient manner. The amount of said compound applied to the fabric is not narrowly critical and can vary,

for example, from 2 to 15 weight percent of solids of said compound based on the dry weight of fabric. The particular concentration of solids in said aqueous solutions of the crease-proofing compound is not narrowly critical and, to a large extent, will depend upon the most convenient wet pick-up of the compound on the fabric with regard to the equipment being used and the desired production schedules. In general, a 50 to 100 percent Wet pick-up based on the dry weight of fabric is advantageous and a wet pick-up in the neighborhood of 65 to 70 percent is preferred.

After impregnation, the fabric is heated at an elevated temperature in the absence of curing catalysts toset the contained crease-proofing compound. This step is best conducted at temperatures of about 130 C. to about 200 C. for about 30 seconds to about 5 minutes, the longer curing times being used for the lower curing temperatures.

After setting in the absence of curing catalyst, the fabric is treated with a suitable curing catalyst such as any of those known in the textile field. Such curing catalysts include any of the basic or acidic curing catalysts heretofore known, for example, zinc nitrate, zinc chloride, magnesium chloride, isopropanolamine hydrochloride, ammonium chloride, benzyldimethylamine oxalate, ammonium phosphate or mixtures thereof. The amount of catalyst applied to the fabric is not narrowly critical and can range from about 2 weight percent to about 60 weight percent of the crease-proofing compound in the fabric. The catalyst is most conveniently applied as an aqueous solution and can be applied by padding, spraying, doctoring or any other suitable means. Other ingredients can be mixed with the catalyst, e.g., wetting agents, or agents for providing the special effects mentioned above, and ingredients that are normally incompatible when mixed with the crease-proofing compound employed can be applied to the fabric at this point.

If desired, the set fabric can be washed prior to application of the curing catalyst. While it is not essential, such washing may be used to further reduce odors or discoloration or other undesirable components.

After application of the catalyst, with or without other ingredients, the fabric is dried. Ambient temperatures can be used or moderately elevated temperatures can be used to dry the fabric. The conditions of drying are selected to avoid curing or to provide only partial curing of the crease-proofing compound in the fabric, as desired.

There results a sensitized fabric which can be shipped and/or stored prior to manufacture of garments therefrom and which can be cut and sewn into garments, then pressed and cured to provide durable press garments which durably retain the shape in which they are finally cured. Final curing of the fabric, whether made up into pressed garments or not, is best conducted at temperatures of 130 C. to 200 C. for 30 seconds to 5 minutes, the longer times being used for the lower temperatures.

Cellulosic textiles used in the present invention include fabrics made of 100% cotton or rayon as well as fabrics made from cotton or rayon blended with synthetic fibers such as polyester fibers, nylon fibers, acrylonitrile and modified acrylonitrile fibers, and the like.

The following examples are presented. Unless otherwise specified, the percentages and parts set forth in the Examples are by weight and the temperatures set forth are in degrees centigrade. The crease-resistance values were determined by the Monsanto Crease Recovery Test (AATCC Tentative Test Method 661959T). The filling tensile strength values were obtained in accordance with the Grab method and the filling tear strength values were obtained in accordance with the Trapezoid method. The appearance ratings were determined by AATCC Tentative Test Method 88-1960 and crease retention values were determined by AATCC Tentative Test 88-C-l962T.

EXAMPLE 1 An aqueous solution containing 24% of a 32% solids aqueous solution of 1,3-dimethoxymethyl-4,5-dihydroxy- 4 2-imidazolidinone was padded onto an all cotton twill to a Wet pick-up. The impregnated fabric was air dried and then heated at 340 F. for seconds.

Thereafter, a catalyst bath was prepared containing 2% of a 64% solids aqueous solution of magnesium chloride hexahydrate and 0.01% of a non-ionic wetting agent (Triton X-lO O, alkylaryl polyglycol ethers sold by Rohm & Haas). The catalyst bath was padded onto the previously set fabric to a 65 wet pick-up. The impregnated fabric was then dried.

The resulting fabric was almost completely free of formaldehyde odor. It was capable of being cured in the flat to produce crease-resistant fabrics or of being rolled on tubes and shipped to garment manufacturers for use in making durable press garments.

A portion of the resulting fabric was cured in the fiat and another portion was formed into a garment trouser leg having a crease and cuif. Both portions were cured at 340 F. for 4 minutes and were found to have a crease-resistance of 256, a tensile strength of 78 pounds and an appearance rating after five home washes of 5. The garment component was found to have a crease retention rating of 5 after five home washes.

EXAMPLE 2 The process of Example 1 is repeated using, however, an equal weight of 1,3-dimethylol-4,5-dihydroxy-2- imidazolidinone in place of 1,3-dimethoxymethyl-4,5-dihydroxy-Z-imidazolidinone. Similar results are obtained.

EXAMPLE 3 In comparison, Example 2 is repeated wherein, however, the catalyst and the 1,3-dimethylol-4,5-dihydroxy-2- imidazolidinone are present in the same aqueous bath and are applied to the fabric in the same respective amounts as those referred to in Example 2. However, the impregnated fabric is dried and partly cured at 280 F. for 70 seconds instead of at 340 F. for 70 seconds. At this point the fabric has considerably more odor than the fabric of Example 2 after the catalyst impregnation and drying. Thereafter, the fabric is finally cured as in Example 2. The resulting fabric has a crease-resistance of 246 and a tensile strength of 76 pounds.

Example 1 is also repeated twice using, respectively, zinc nitrate and zinc chloride in place of magnesium chloride and similar advantageous results are obtained in both cases. In addition, when a urea-formaldehyde condensate, an ethylene urea-formaldehyde condensate, an ethyltriazone-formaldehyde condensate and a melamineformaldehyde condensate are separately substituted for the 1,3-di-methoxymethyl-4,S-dihydroxy-Z-imidazolidinone in Example 1, similar advantageous results are obtained.

The 1,3-dimethoxymethyl-4,5-dihydroxy 2 imidazolidinone aqueous solution used in Example 1 was prepared as follows:

An aqueous solution (360 grams) containing about 50% solids of 1,3-dimethylol-4,S-dihydroxy-Z-imidazolidinone was concentrated at 12 cm. vacuum for 2 hours to a concentration of about solids. 360 grams of methanol were added to the concentrated solution and the initial pH was measured at 6.3. One gram of concentrated hydrochloric acid was added to bring the pH down to 1.4. The solution resulting was heated to 60 C. and held there for one hour. To the reaction solution was added 1 gram of 25% aqueous sodium hydroxide to bring the pH of the solution to 5.5 The novel composition thus prepared was an aqueous solution containing 32% solids.

What is claimed is:

1. In a process of producing crease-resistant textiles comprising impregnating a cellulosic textile with a solution or dispersion of a crease-proofing nitrogen-containing compound selected from the class consisting of ureaformaldehyde condensates, ethylene urea-formaldehyde condensates, formaldehyde condensates of 4,5-dihydroxy- Z-imidazolidinone, melamine-formaldehyde condensates, triazone-formaldehyde condensates and lower alkylated derivatives thereof and an acidic or basic curing catalyst for said crease-proofing compound; and heating the impregnated textile at a temperature in the range of about 130 C. to about 200 C. for about 30 seconds to about 5 minutes to cure the resulting impregnated textile and impart crease-resistance thereto, that improvement comprising, conducting said impregnating step in the absence of said acidic or basic catalyst; conducting said heating step to dry and set the resulting impregnated textile in the absence of said catalyst; additionally impregnating the resulting dried and set textile with said acidic or basic catalyst for said crease-proofing compound; and drying the resulting catalyst-impregnated textile to a condition suitable for shipment.

2. Process as claimed in claim 1 wherein said creaseproofing compound is a formaldehyde condensate of 4,5- dihydroxy-Z-irnidazolidinone.

3. Process as claimed in claim 2 wherein said catalyst applied to said dried and set textile is magnesium chloride.

4. Process as claimed in claim 1 wherein said creaseproofing compound is 1,3-dimethoxymethyl-4,S-dihydroxy-2-imidazolidinone.

5. Process as claimed in claim 4 wherein said catalyst applied to said dried and set textile is magnesium chloride.

6. Process as claimed in claim 1 wherein said dried, catalyst-impregnated textile is made up into a garment, pressed and cured to form a durable press garment.

7. Textile produced by the process claimed in claim 2 wherein said catalyst-impregnated, dried and set fabric is not more than partially cured.

8. Textile produced by the process claimed in claim 4 wherein said catalyst-impregnated, dried and set fabric is not more than partially cured.

References Cited UNITED STATES PATENTS 2,950,553 8/1960 Hurwitz 38144 JOHN DAVID WELSH, Primary Examiner US. Cl. X.R. 

